Heavy metals such as copper, zinc, and lead are common pollutants in solution and in suspension in industrial storm water runoff in the U.S. The U.S. Environmental Protection Agency regulates the quantity, quality, and ongoing monitoring of storm water runoff from industrial facility sites pursuant to Multi-Sector General Storm Water regulations contained in the Clean Water Act.
Heavy metals exist in industrial runoff primarily from rainfall contact with automobiles, tire wear, brake pad wear, hydraulic oil, engine oil, building structures, specifically metal roofs, gutters, and metal siding, as well as construction residue, asphalt treatments, machining and manufacturing waste, metal primers and paint, and any exposed materials that may be stored externally at a facility. Particularly when rain falls at a high rate, as during a storm, and after a period of little precipitation, storm water runoff from an industrial area may carry significant amounts of contaminants.
There is little to no published literature or research on the control and mitigation of storm water runoff from industrial sites. There is however substantial state and federal regulation of storm water runoff from industrial sites. The result is that industrial sites often find themselves with permits for storm water discharge that limit constituents such as chemical oxygen demand, total suspended solids, oil and grease, turbidity or color, and limit metals such as copper, zinc, and lead, all of which may be construed to be deleterious to downstream receiving water bodies.
Various structures and methods for removing various suspended and dissolved impurities from storm water are disclosed in, for example, Stewart et al., U.S. Pat. No. 5,322,622; Herman et al., U.S. Pat. No. 7,037,423; Knutson et al., U.S. Pat. No. 5,707,527; Lenhart, Jr. et al., U.S. Pat. No. 6,027,639; Allen II et al., U.S. Pat. No. 8,110,105; Aberle et al., U.S. Pat. No. 7,214,311; Aberle et al., U.S. Pat. No. 7,419,591; Hersey et al., U.S. Pat. No. 7,517,450; Hersey et al., U.S. Pat. No. 8,110,099; Buelna, U.S. Pat. No. 6,100,081; Lambert, V et al., U.S. Pat. No. 8,216,479; Adams et al., U.S. Pat. No. 8,147,688; and Schluter et al., U.S. Pat. No. 7,186,058.
Various shortcomings in treatment of storm water runoff remain despite the prior art mentioned above, in that the storm water treatment apparatus disclosed is undesirably expensive to manufacture and maintain, that large areas of land may be required to contain various components of such systems, and that the effectiveness of the storm water treatment systems previously available is less than desired.
What is desired, then, is a storm water treatment system that can be constructed at a moderate cost, that is not particularly complex, and that is more effective than previously known storm water treatment systems.